The present invention relates to a photosensitive resin composition of aqueous emulsion type.
More particularly, the present invention relates to a photosensitive resin composition of aqueous emulsion type which are developable with water or a dilute aqueous alkaline solution and are useful particularly as photoresist ink for manufacturing printed wiring boards.
Moreover, the present invention relates to a photosensitive resin composition which has a good sensitivity and a water and solvent resistance. The present photosensitive resin composition is useful for screen printing stencil and photosensitive printing ink. The composition is also useful for etching resist, plating resist ink and solder resist ink for manufacturing printed wiring boards.
A photoresist ink developable with a dilute aqueous alkaline solution requires no use to solvent to develop. Such kind of ink is superior to develop with industrial safety, and with prevention of environmental pollution or fire. Therefore, in recent years, they have been often used in the fields of ink for manufacturing printed wiring boards, ink for carving gravure rolls, ink for manufacturing color filter pixels, photosensitive composition for manufacturing screen printing stencils and ink for manufacturing color filter protective coatings. Conventional photoresist ink developable with a dilute aqueous alkaline solution includes a photosensitive resin composition such as those disclosed in JP-A 5-224413 and JP-A 5-241340, for example.
However, the above mentioned photoresist ink developable with a dilute aqueous alkaline solution generally has some ingredients which are dissolved or dispersed in various kinds of organic solvents so that the ink of the ingredients is uniformly applied to the surface of a substrate and then subjected to an exposure and to transfer to the next development process. Therefore, it is necessary to vaporize the organic solvent by predrying before exposure. Thus, the use of an organic solvent causes a problem of industrial safety, environmental pollution, fire control and so on, which is remained unsettled in the process of forming a predried film after its application to a substrate.
Accordingly, there is an object of the present invention to be solved to provide a photosensitive resin composition of aqueous emulsion type which can reduce a problem relating to industrial safety, environmental pollution, fire control and so on accompanied by use of an organic solvent in the process of forming a predried film after its application to a substrate. The photosensitive resin composition according to the present invention is useful as a photoresist ink for manufacturing printed wiring boards such as etching resist ink, plating resist ink, solder resist ink and marking ink, a photoresist ink for carving gravure rolls, an ink for manufacturing color filter pixels, a photosensitive composition for manufacturing screen printing stencils, an ink for manufacturing color filter protective coatings and so on and is developable with water or a dilute aqueous alkaline solution.
Furthermore, there has been known a photosensitive resin composition of aqueous emulsion type used widely for manufacturing a screen printing stencil.
Such a known photosensitive resin composition for manufacturing a screen printing stencil includes a composition comprising a diazo resin as photocrosslinking agent, polyvinyl alcohol, a polyvinyl acetate emulsion and so on (see JP-A 53-51004), a composition comprising a water-soluble photosensitive polymer obtained by adding N-methylol(meth)acrylamide to polyvinyl alcohol (see JP-B 49-5923), a composition obtained,by adding an ethylenically unsaturated compound and a photopolymerization initiator to an emulsion of polyvinyl alcohol or polyvinyl acetate having styrylpyridinium or styrylquinolinium group (see JP-A 60-10245).
The above mentioned photosensitive resin composition of aqueous emulsion type for screen printing may be changed into a cured film having a certain water resistance or a solvent resistance. However, in order to produce a screen printing stencil with greater durability, it is demanded that a photosensitive resin composition can be changed into a cured film having greater water resistance and greater solvent resistance.
Accordingly, there is another object to the present invention to be solved to provide a novel photosensitive resin composition of aqueous emulsion type capable of forming a cured film having extremely excellent water and solvent resistances in comparison with conventional photosensitive resin compositions of aqueous emulsion type.
The above mentioned objects are solved to provide an aqueous emulsion type photosensitive resin composition comprising:
(A) an emulsion of a photosensitive water-insoluble polymer, the emulsion being obtained by reacting (i) an aqueous polymer emulsion which contains a water-insoluble polymer as its main component and which contains a polymer having a hydroxyl group with (ii) an N-alkylol(meth)acrylamide;
(B) a compound having a photoreactive ethylenically unsaturated group; and
(C) a photopolymerization initiator.
In this specification, xe2x80x9c(meth)acrylic-xe2x80x9d means xe2x80x9cacrylic-xe2x80x9d and/or xe2x80x9cmethacrylic-xe2x80x9d. For example, (meth)acrylic acid means acrylic acid and/or methacrylic acid, and (meth)acrylamide means acrylamide and/or methacrylamide.